perldoc -f glob
glob EXPR
glob Returns the value of EXPR with filename expansions such as the
standard Unix shell /bin/csh would do. This is the internal
function implementing the "" operator, but you can use it
directly. If EXPR is omitted, $_ is used. The "" operator
is discussed in more detail in "I/O Operators" in perlop.
Beginning with v5.6.0, this operator is implemented using the
standard "File::Glob" extension. See File::Glob for details.